Transmission having at least ten speeds

ABSTRACT

A transmission of the present invention has an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes. The torque transmitting devices are selectively engageable in combinations of at least three to establish at least ten forward speed ratios and at least one reverse speed ratio.

FIELD

The present invention relates generally to a multiple speed transmissionhaving a plurality of planetary gear sets and a plurality of torquetransmitting devices, and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches and brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In an aspect of the present invention, the input member is continuouslyinterconnected with the carrier member of the fourth planetary gear setand output member is continuously interconnected with the carrier memberof the first planetary gear set.

In another aspect of the present invention, a first interconnectingmember continuously interconnects the sun gear of the first planetarygear set with ring gear of the third planetary gear set.

In yet another aspect of the present invention, a second interconnectingmember continuously interconnects the ring gear of the first planetarygear set with the ring gear of the second planetary gear set.

In yet another aspect of the present invention, a third interconnectingmember continuously interconnects the sun gear of the second planetarygear set with the carrier member of the third planetary gear set and thering gear of the fourth planetary gear set.

In yet another aspect of the present invention, a first torquetransmitting device is selectively engageable to interconnect the sungear of the first planetary gear set and the ring gear of the thirdplanetary gear set with the carrier member of the second planetary gearset.

In yet another aspect of the present invention, a second torquetransmitting device is selectively engageable to interconnect thecarrier member of the second planetary gear set with the sun gear of thethird planetary gear set.

In yet another aspect of the present invention, a third torquetransmitting device is selectively engageable to interconnect the sungear of the third planetary gear set with the carrier member of thefourth planetary gear set and the input member.

In yet another aspect of the present invention, a fourth torquetransmitting device is selectively engageable to interconnect the sungear of the third planetary gear set with the sun gear of the fourthplanetary gear set.

In yet another aspect of the present invention, a fifth torquetransmitting device is selectively engageable to interconnect the ringgear of the second planetary gear set with the stationary member.

In yet another aspect of the present invention, a sixth torquetransmitting device is selectively engageable to interconnect the sungear of the fourth planetary gear set with the stationary member, andwherein the torque transmitting devices are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.

Further aspects and advantages of the present invention will becomeapparent by reference to the following description and appended drawingswherein like reference numbers refer to the same component, element orfeature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that in the particular exampleprovided, the ten speed automatic transmission of the present inventionhas an arrangement of permanent mechanical connections between thecomponents or elements of the four planetary gear sets. A firstcomponent or element of the first planetary gear set is permanentlycoupled to a third component or element of a third planetary gear set. Athird component or element of the first planetary gear set ispermanently coupled to a third component or element of a secondplanetary gear set. A first component or element of a second planetarygear set is permanently coupled to a second component or element of athird planetary gear set and a third component or element of a fourthplanetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear set are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear, one for the planet gearcarrier, and one for the ring gear. In some cases, two levers may becombined into a single lever having more than three nodes (typicallyfour nodes). For example, if two nodes on two different levers areinterconnected through a fixed connection they may be represented as asingle node on a single lever. The relative length between the nodes ofeach lever can be used to represent the ring-to-sun ratio of eachrespective gear set. These lever ratios, in turn, are used to vary thegear ratios of the transmission in order to achieve appropriate ratiosand ratio progression. Mechanical couplings or interconnections betweenthe nodes of the various planetary gear sets are illustrated by thin,horizontal lines and torque transmitting devices such as clutches andbrakes are presented as interleaved fingers. If the device is a brake,one set of the fingers is grounded. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14, a second planetary gear set 16, a third planetarygear set 18, a fourth planetary gear set 20 and an output shaft ormember 22. In the lever diagram of FIG. 1, the first planetary gear set14 has three nodes each: a first node 14A, a second node 14B and a thirdnode 14C. The second planetary gear set 16 has three nodes each: a firstnode 16A, a second node 16B and a third node 16C. The third planetarygear set 18 has three nodes each: a first node 18A, a second node 18Band a third node 18C. The fourth planetary gear set 20 has three nodeseach: a first node 20A, a second node 20B and a third node 20C.

The first node 14A of the first planetary gear set 14 is coupled to thethird node 18C of the third planetary gear set 18. The third node 14C ofthe first planetary gear set 14 is coupled to the third node 16C of thesecond planetary gear set 16. The first node 16A of the second planetarygear set 16 is coupled to the second node 18B of the third planetarygear set 18 and to the third node 20C of the fourth planetary gear set20. The input member 12 is coupled to the second node 20B of the fourthplanetary gear set 20. The output member 22 is coupled to the secondnode 14B of the first planetary gear set 14.

A first clutch 24 selectively connects the first node 14A of the firstplanetary gear set 14 and the third node 18C of the third planetary gearset 18 with the second node 16B of the second planetary gear set 16. Asecond clutch 26 selectively connects the second node 16B of the secondplanetary gear set 16 with the first node 18A of the third planetarygear set 18. A third clutch 28 selectively connects the first node 18Aof the third planetary gear set 18 with the second node 20B of thefourth planetary gear set 20 and the input member 12. A fourth clutch 30selectively connects the first node 18A of the third planetary gear set18 with the first node 20A of the fourth planetary gear set 20. A firstbrake 32 selectively connects the third node 16C of the second planetarygear set 16 with a stationary element or a transmission housing 50. Asecond brake 34 selectively connects the first node 20A of the fourthplanetary gear set 20 with the stationary element or a transmissionhousing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches, brakes, and couplings are correspondinglypresented whereas the nodes of the planetary gear sets now appear ascomponents of planetary gear sets such as sun gears, ring gears, planetgears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14A, aring gear member 14C and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). Theplanet gears 14D are each configured to intermesh with both the sun gearmember 14A and the ring gear member 14C. The sun gear member 14A isconnected for common rotation with a first shaft or interconnectingmember 42. The ring gear member 14C is connected for common rotationwith a second shaft or interconnecting member 44. The planet carriermember 14B is connected for common rotation with the output shaft ormember 22.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa first set of planet gears 16D (only one of which is shown) and asecond set of planet gears 16E (only one of which is shown). The planetgears 16D are each configured to intermesh with both the sun gear member16A and second set of planet gears 16E. The planet gears 16E are eachconfigured to intermesh with both the ring gear member 16C and first setof planet gears 16D. The sun gear member 16A is connected for commonrotation with a third shaft or interconnecting member 46. The ring gearmember 16A is connected for common rotation with the second shaft orinterconnecting member 44. The planet carrier member 16B is connectedfor common rotation with a fourth shaft or interconnecting member 48 anda fifth shaft or interconnecting member 52.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The set ofplanet gears 18D are each configured to intermesh with both the sun gearmember 18A and the ring gear member 18C. The sun gear member 18A isconnected for common rotation with a sixth shaft or interconnectingmember 54. The ring gear member 18C is connected for common rotationwith the first shaft or interconnecting member 42. The planet carriermember 18B is connected for common rotation with the third shaft orinterconnecting member 46 and with a seventh shaft or interconnectingmember 56.

The planetary gear set 20 includes a sun gear member 20A, a ring gearmember 20C and a planet gear carrier member 20B that rotatably supportsa first set of planet gears 20D (only one of which is shown). The set ofplanet gears 20D are each configured to intermesh with both the sun gearmember 20A and the ring gear member 20C. The sun gear member 20A isconnected for common rotation with an eighth shaft or interconnectingmember 58. The ring gear member 20C is connected for common rotationwith the sixth shaft or interconnecting member 56. The planet carriermember 20B is connected for common rotation with a ninth shaft orinterconnecting member 60 and with the input shaft or member 12.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or first clutch 24, second clutch 26,third 28, fourth 30 and brakes 32 and 34 allow for selectiveinterconnection of the shafts or interconnecting members, members of theplanetary gear sets and the housing. For example, the first clutch 24 isselectively engageable to connect the first shaft or interconnectingmember 42 with the fifth shaft or interconnecting member 52. The secondclutch 26 is selectively engageable to connect the fourth shaft orinterconnecting member 48 with the sixth shaft or interconnecting member54. The third clutch 28 is selectively engageable to connect the sixthshaft or interconnecting member 54 with the ninth shaft orinterconnecting member 60. The fourth clutch 30 is selectivelyengageable to connect the sixth shaft or interconnecting member 54 withthe eighth shaft or interconnecting member 58. The first brake 32 isselectively engageable to connect the ring gear member 16C of the secondplanetary gear set 16 with a stationary element or the transmissionhousing 50 in order to prevent the member 16C from rotating relative tothe transmission housing 50. The second brake 34 is selectivelyengageable to connect the eighth shaft or interconnecting member 58 witha stationary element or the transmission housing 50 in order to preventthe eighth shaft or interconnecting member 58 from rotating relative tothe transmission housing 50.

Referring now to FIGS. 2 and 3, the operation of the embodiment of theten speed transmission 10 will be described. It will be appreciated thatthe transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with triple overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 24, second clutch 26,third clutch 28, fourth clutch 30, first brake 32 and second brake 34),as will be explained below. FIG. 3 is a truth table presenting thevarious combinations of torque-transmitting elements that are activatedor engaged to achieve the various gear states. Actual numerical gearratios of the various gear states are also presented although it shouldbe appreciated that these numerical values are exemplary only and thatthey may be adjusted over significant ranges to accommodate variousapplications and operational criteria of the transmission 10. An exampleof the gear ratios that may be obtained using the embodiments of thepresent invention are also shown in FIG. 3. Of course, other gear ratiosare achievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

To establish reverse gear, the first clutch 24, the first brake 32 andthe second brake 34 are engaged or activated. The first clutch 24selectively interconnects the first shaft or interconnecting member 42with the fifth shaft or interconnecting member 52. The first brake 32connects the ring gear member 16C of the second planetary gear set 16with a stationary element or the transmission housing 50 in order toprevent the member 16C from rotating relative to the transmissionhousing 50. The second brake 34 connects the eighth shaft orinterconnecting member 58 with a stationary element or the transmissionhousing 50 in order to prevent the eighth shaft or interconnectingmember 58 from rotating relative to the transmission housing 50.Likewise, the ten forward ratios are achieved through differentcombinations of clutch and brake engagement, as shown in FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches and brakes not specifically referenced in a given gearstate are inactive or disengaged and, second of all, that during gearshifts, i.e., changes of gear state, between at least adjacent gearstates, a clutch or brake engaged or activated in both gear states willremain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the first member of the first planetary gear set withthird member of the third planetary gear set; a second interconnectingmember continuously interconnecting the third member of the firstplanetary gear set with the third member of the second planetary gearset; a third interconnecting member continuously interconnecting thefirst member of the second planetary gear set with the second member ofthe third planetary gear set and the third member of the fourthplanetary gear set; and six torque transmitting devices each selectivelyengageable to interconnect at least one of the first, second, and thirdmembers with at least one other of the first members, second members,third members, and a stationary member, and wherein the torquetransmitting devices are selectively engageable in combinations of atleast three to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member.2. The transmission of claim 1 wherein a first of the six torquetransmitting devices is selectively engageable to interconnect the firstmember of the first planetary gear set and the third member of the thirdplanetary gear set with the second member of the second planetary gearset.
 3. The transmission of claim 2 wherein a second of the six torquetransmitting devices is selectively engageable to interconnect thesecond member of the second planetary gear set with the first member ofthe third planetary gear set.
 4. The transmission of claim 3 wherein athird of the six torque transmitting devices is selectively engageableto interconnect the first member of the third planetary gear set withthe second member of the fourth planetary gear set and the input member.5. The transmission of claim 4 wherein a fourth of the six torquetransmitting devices is selectively engageable to interconnect the firstmember of the third planetary gear set with the first member of thefourth planetary gear set.
 6. The transmission of claim 5 wherein afifth of the six torque transmitting devices is selectively engageableto interconnect the third member of the second planetary gear set withthe stationary member.
 7. The transmission of claim 6 wherein a sixth ofthe six torque transmitting devices is selectively engageable tointerconnect the first member of the fourth planetary gear set with thestationary member.
 8. The transmission of claim 1 wherein the firstmember of the first, second, third and fourth planetary gear sets aresun gears, the second member of the first, second, third and fourthplanetary gear set are carrier members and the third member of thefirst, second, third and fourth planetary gear sets are ring gears. 9.The transmission of claim 1 wherein the input member is continuouslyinterconnected with the second member of the fourth planetary gear setand output member is continuously interconnected with the second memberof the first planetary gear set.
 10. The transmission of claim 1 whereinfour of the six torque transmitting devices are clutches and two of thesix torque transmitting devices are brakes.
 11. The transmission ofclaim 1 wherein the stationary member is a transmission housing.
 12. Atransmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members, wherein the input member is continuouslyinterconnected with the second member of the fourth planetary gear setand output member is continuously interconnected with the second memberof the first planetary gear set; a first interconnecting membercontinuously interconnecting the first member of the first planetarygear set with third member of the third planetary gear set; a secondinterconnecting member continuously interconnecting the third member ofthe first planetary gear set with the third member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe second member of the third planetary gear set and the third memberof the fourth planetary gear set; a first torque transmitting deviceselectively engageable to interconnect the first member of the firstplanetary gear set and the third member of the third planetary gear setwith the second member of the second planetary gear set; a second torquetransmitting device selectively engageable to interconnect the secondmember of the second planetary gear set with the first member of thethird planetary gear set; a third torque transmitting device selectivelyengageable to interconnect the first member of the third planetary gearset with the second member of the fourth planetary gear set and theinput member; a fourth torque transmitting device selectively engageableto interconnect the first member of the third planetary gear set withthe first member of the fourth planetary gear set; a fifth torquetransmitting device selectively engageable to interconnect the thirdmember of the second planetary gear set with the stationary member; anda sixth torque transmitting device selectively engageable tointerconnect the first member of the fourth planetary gear set with thestationary member, and wherein the torque transmitting devices areselectively engageable in combinations of at least three to establish atleast ten forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.
 13. The transmission ofclaim 12 wherein the first member of the first, second, third and fourthplanetary gear sets are sun gears, the second member of the first,second, third and fourth planetary gear set are carrier members and thethird member of the first, second, third and fourth planetary gear setsare ring gears.
 14. The transmission of claim 12 wherein the stationarymember is a transmission housing.
 15. A transmission comprising: aninput member; an output member; first, second, third and fourthplanetary gear sets each having a sun gear, a carrier member and a ringgear, wherein the input member is continuously interconnected with thecarrier member of the fourth planetary gear set and output member iscontinuously interconnected with the carrier member of the firstplanetary gear set; a first interconnecting member continuouslyinterconnecting the sun gear of the first planetary gear set with ringgear of the third planetary gear set; a second interconnecting membercontinuously interconnecting the ring gear of the first planetary gearset with the ring gear of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the sun gear of thesecond planetary gear set with the carrier member of the third planetarygear set and the ring gear of the fourth planetary gear set; a firsttorque transmitting device selectively engageable to interconnect thesun gear of the first planetary gear set and the ring gear of the thirdplanetary gear set with the carrier member of the second planetary gearset; a second torque transmitting device selectively engageable tointerconnect the carrier member of the second planetary gear set withthe sun gear of the third planetary gear set; a third torquetransmitting device selectively engageable to interconnect the sun gearof the third planetary gear set with the carrier member of the fourthplanetary gear set and the input member; a fourth torque transmittingdevice selectively engageable to interconnect the sun gear of the thirdplanetary gear set with the sun gear of the fourth planetary gear set; afifth torque transmitting device selectively engageable to interconnectthe ring gear of the second planetary gear set with the stationarymember; and a sixth torque transmitting device selectively engageable tointerconnect the sun gear of the fourth planetary gear set with thestationary member, and wherein the torque transmitting devices areselectively engageable in combinations of at least three to establish atleast ten forward speed ratios and at least one reverse speed ratiobetween the input member and the output member.
 16. The transmission ofclaim 15 wherein the stationary member is a transmission housing.